Silvia Ioan

By Silvia Ioan and Anca Filimon

Part of the book: A Search for Antibacterial Agents

By Andreea Irina Barzic and Silvia Ioan

Infections caused by diverse bacteria represent a major problem that threats the health of humans. This stimulates the scientists to find new solutions for treating these diseases by clarifying the interactions of antibacterial compounds with the biological medium. In this context, the chapter presents some basic concepts regarding the antibacterial drugs. The synthesis routes of novel compounds and specific design techniques with polymer materials are described in correlation with the in vitro and in vivo activity of antibacterial substances. Essential data about the mechanism of action, selected in vivo efficacy and mechanisms of resistance to the most used antibacterial drugs are reviewed.

Part of the book: Concepts, Compounds and the Alternatives of Antibacterials

By Andreea Irina Barzic and Silvia Ioan

Some basic concepts regarding the viscoelastic properties of polymers in solution phase, highlighting the effects of the some experimental variables, such as system composition, temperature or time, are reviewed. The main attention is given to experiments involving shear deformation of polymer solutions, since it provides the most significant data concerning the optimal processing of final product. The response of polymers to a mechanical perturbation involves several types of molecular motions, which are reflected in the microstructure changes. The elastic constants, which determine the motion of macromolecules, become anisotropic in case of liquid-crystal polymer (LCP). The state of art concerning the viscoelastic behavior of liquid crystal polymers in composite systems is described. The main aspects that are discussed include the effects on the viscoelasticity given by molecular orientation, system composition and interactions. Finally, some particular cases are presented to illustrate the potential applications of these principles to practical problems in the processing and use of the described materials.

Part of the book: Viscoelastic and Viscoplastic Materials